1. Field of the Invention
The present disclosure relates to a technical field regarding a wet developing method, which is one of the electrophotographic systems that can be adopted in printers, copy machines, facsimile machines, or multi-functional peripherals having these functions.
2. Description of the Related Art
Developing systems used in an electrophotographic method for rendering an electrostatic latent image with electrically charged colored particles are generally classified roughly into a dry developing method and a wet developing method, depending on the type of the developer used. The wet developing method uses a liquid developer having colored particles dispersed within an electrically insulating carrier liquid. The colored particles electrically charged within the liquid developer moves from a developing roller surface to a photoreceptor drum surface according to the principle of electrophoresis, in order to render an electrostatic latent image on the photoreceptor drum surface into a toner image. The obtained toner image is transferred from the photoreceptor drum to a recording medium. The colored particles of the liquid developer are hardly scattered into the atmosphere, and therefore fine particles with, for example, submicron-sized average particle diameter can be used. Thus, high-quality, high-resolution images with excellent gradation can be obtained.
When an image forming apparatus using the wet developing method is continuously driven without printing anything or to print very few, the carrier liquid accumulates in a nip between the photoreceptor and an intermediate transfer body (intermediate transfer system) or a nip between the photoreceptor and a sheet (direct transfer system), causing bleeding. The bleeding is particularly noticeable when starting to drive the image forming apparatus, or between sheets when the image forming apparatus is used for continuous printing, because the entire image surface is a non-image area in those cases.
As a way to prevent the occurrence of bleeding, there has been reported technology for stabilizing the dispersion of a liquid toner by using a specific pigment, so as to prevent bleeding in images.
This conventional method, however, cannot use different-colored pigments other than a specific pigment because the use of other pigments still causes the bleeding. An object of the present disclosure is to provide a liquid developer, a liquid developing device, a wet image forming apparatus, and a wet image forming method, which are capable of preventing the occurrence of bleeding even when using a variety of pigments.